Acetylcholine has been implicated in the normal function of the visual cortex and in ocular dominance plasticity. We used antibodies to localize muscarinic cholinergic receptor proteins m1 to m4 in striate cortex of monkeys whose ocular dominance system had been altered by several methods of visual deprivation, and compared the distribution pattern of these proteins in the deprived with that in normal monkeys. In normal striate cortex, immunoreactivity of all four proteins is differentially distributed in complex laminar patterns. m1 was densest in layers 2, 3, and 6, followed by layer 5. In contrast, m2 reactivity was densest in lower layer 4C and in 4A; the latter exhibited a honeycomb pattern. Layers 2 and 3 displayed alternating dense and light regions, similar to CytOx blobs. The m2 reaction product, however, occupied the interblob regions as defined in CytOx sections. Laminar immunoreactivity for m3 receptor was also similar to the CytOx pattern, including a hon eycomb pattern in 4A. Antibody to m4 reacted most densely with layers 1, 2, 3, and 5, layers 2 and 3 exhibited a blob-like distribution pattern, layer 4A had a faint honeycomb. Layer 4C was the lightest band. In monkeys raised from birth with a black contact lens on one eye, in one lidsutured monkey, and in one monkey with a suspected long-term retinal injury, the laminar distribution patterns and densities of immunoreactivity of the 4 receptor proteins were not different from normal. Lidsuture lasting for 3.5 months caused some alterations of m1 reactivity in layer 6. Thus, the four muscarinic receptor subtypes are differentially distributed, suggesting distinct roles in cholinergic modulation of visual processing. However, they all appear to be insensitive to elimination of visual input via monocular occlusion from birth, to deprivation of pattern vision in one eye during a specific time period in adulthood, and to long-term retinal injury. These experiments were supported by EY09737 to M. Tigges and NS30454 to A. Levey.